Allocated but unannounced space
Every block here was allocated or assigned by a regional internet registry, and none of them appeared in any routing table we collected at our last snapshot — neither as a route of their own, nor covered by a larger announcement, nor carved up into more specifics.
“Unannounced” does not mean “unused”
Plenty of allocated space is deliberately kept off the public internet: private interconnects, lab and lawful-intercept ranges, networks reachable only inside one operator, and space held in reserve. Some of it is announced somewhere our collectors cannot see, which is a limit of our vantage points rather than a fact about the block.
It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today. Nothing on this page means a block is unallocated, available, or free to announce.
Browse by registry
Browse by country
Countries with unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,315 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 204.110.128.0/20 | 4.1k | ARIN |  US | 5th Oct 1994 |
| 204.110.144.0/20 | 4.1k | ARIN | US | 11th Oct 1994 |
| 204.110.176.0/21 | 2k | ARIN | US | 19th Oct 1994 |
| 204.110.184.0/23 | 512 | ARIN | US | 19th Oct 1994 |
| 204.110.240.0/20 | 4.1k | ARIN | US | 18th Nov 1994 |
| 204.110.64.0/20 | 4.1k | ARIN | US | 19th Sept 1994 |
| 204.110.80.0/20 | 4.1k | ARIN | US | 23rd Sept 1994 |
| 204.114.10.0/23 | 512 | ARIN | US | 11th May 2011 |
| 204.114.16.0/21 | 2k | ARIN | US | 15th Sept 1994 |
| 204.114.64.0/18 | 16.4k | ARIN | US | 22nd Sept 1994 |
| 204.115.100.0/24 | 256 | ARIN | US | 28th Sept 1994 |
| 204.115.112.0/22 | 1k | ARIN | US | 30th Sept 1994 |
| 204.115.116.0/24 | 256 | ARIN | US | 30th Sept 1994 |
| 204.115.118.0/23 | 512 | ARIN | US | 18th May 2011 |
| 204.115.12.0/23 | 512 | ARIN | US | 19th Sept 1994 |
| 204.115.124.0/23 | 512 | ARIN | US | 30th Sept 1994 |
| 204.115.136.0/21 | 2k | ARIN | US | 4th Oct 1994 |
| 204.115.148.0/23 | 512 | ARIN | US | 4th Oct 1994 |
| 204.115.152.0/21 | 2k | ARIN | US | 6th Oct 1994 |
| 204.115.160.0/21 | 2k | ARIN | US | 7th Oct 1994 |
| 204.115.206.0/23 | 512 | ARIN | US | 7th Mar 2011 |
| 204.115.208.0/21 | 2k | ARIN | US | 24th Oct 1994 |
| 204.115.22.0/23 | 512 | ARIN | US | 21st Jun 2019 |
| 204.115.232.0/21 | 2k | ARIN | US | 26th Oct 1994 |
| 204.115.24.0/21 | 2k | ARIN | US | 22nd Sept 1994 |
| 204.115.240.0/21 | 2k | ARIN | US | 26th Oct 1994 |
| 204.115.248.0/22 | 1k | ARIN | US | 26th Oct 1994 |
| 204.115.252.0/23 | 512 | ARIN | US | 19th Aug 2026 |
| 204.115.32.0/20 | 4.1k | ARIN | US | 8th Aug 1994 |
| 204.115.48.0/21 | 2k | ARIN | US | 8th Aug 1994 |
| 204.115.56.0/22 | 1k | ARIN | US | 8th Aug 1994 |
| 204.115.60.0/23 | 512 | ARIN | US | 8th Aug 1994 |
| 204.115.72.0/21 | 2k | ARIN | US | 27th Sept 1994 |
| 204.115.8.0/22 | 1k | ARIN | US | 19th Sept 1994 |
| 204.115.87.0/24 | 256 | ARIN | US | 17th Apr 2012 |
| 204.115.88.0/21 | 2k | ARIN | US | 27th Sept 1994 |
| 204.115.96.0/22 | 1k | ARIN | US | 28th Sept 1994 |
| 204.122.0.0/21 | 2k | ARIN | US | 22nd Aug 1994 |
| 204.122.17.0/24 | 256 | ARIN | US | 15th Nov 2023 |
| 204.122.32.0/19 | 8.2k | ARIN | US | 25th Aug 1994 |
| 204.124.10.0/24 | 256 | ARIN | US | 4th Oct 1994 |
| 204.124.108.0/22 | 1k | ARIN | US | 19th Oct 1994 |
| 204.124.112.0/23 | 512 | ARIN | US | 19th Oct 1994 |
| 204.124.114.0/24 | 256 | ARIN | US | 19th Oct 1994 |
| 204.124.115.0/24 | 256 | ARIN | US | 8th Jul 2026 |
| 204.124.124.0/22 | 1k | ARIN | US | 24th Oct 1994 |
| 204.124.148.0/22 | 1k | ARIN | US | 8th Nov 1994 |
| 204.124.16.0/23 | 512 | ARIN | US | 5th Oct 1994 |
| 204.124.164.0/23 | 512 | ARIN | US | 14th Nov 1994 |
| 204.124.176.0/22 | 1k | ARIN | US | 21st Nov 1994 |